Field of the Invention
The invention is in the field of multichannel electrooptical connections and relates to an electrooptical coupling component, including a first substrate with a first alignment device and a plurality of optical waveguides located in one plane and having coupling-side end surfaces causing a beam deflection to optically active surfaces of a multichannel electrooptical converter, the optically active surfaces oriented toward the optical waveguides, and a second substrate with a second alignment device tuned or matched to the first alignment device of the first substrate, the electrooptical converter positioned on the second substrate independently of the optical waveguides and precisely with respect to the second alignment device.
Within the scope of the invention, an optical waveguide is understood to mean any device for carrying an optical signal in a three-dimensionally defined, guided way, especially ready-made optical waveguides and so-called fiber optics. In addition, an electrooptical converter is understood as both a transmitting and a receiving element (for instance light emitting diodes, surface emitting laser diodes, and photo diodes), in which the optically active surface of the converter for a transmitter is a light-emitting surface, while for a receiver it is a light-sensitive surface.
An optical transmitting and receiving device with a first substrate is known from European Patent Application EP 0 713 112 A1. A transmitter element is disposed on the first substrate in a recess. A second substrate is provided with a groove, in order to receive an optical waveguide on its lower surface. The optical waveguide ends at a protrusion having a triangular cross section that extends crosswise to the groove. The protrusion divides the groove from a recess on a lower surface of the second substrate. The two substrates are disposed on opposed sides of an intermediate body. The first substrate has its transmitter element facing a lower surface of the second substrate. Coupling of the optical waveguide to the transmitter element is accomplished by reflection of the beam, emitted by the transmitter element, from one side of the protrusion. A lens that focuses the beam is additionally provided on the intermediate body for adequate coupling efficiency. The alignment of the two substrates with one another is carried out through the use of adjusting balls, which cooperate with indentations in the intermediate body and in the substrate. The transmitting and receiving device is complicated to produce because the adjustment balls have to be manipulated as separate elements, and it involves losses because the beam has to penetrate the intermediate body.
An article entitled "Photonic Interconnections: More Bandwidth, Less Real Estate" by Eric R. Fossum, in PHOTONICS SPECTRA, May 1987, pages 151-157, describes an electrooptical coupling component with a first silicon substrate into which V-shaped grooves are etched. Ends of optical waveguides placed in the grooves are polished obliquely along with an end surface of the silicon substrate. Radiation guided in the ends of the optical waveguides reaches planar-structured optical receivers by way of the thus-formed oblique end surfaces. The lateral adjustment of the optical waveguides with respect to the receivers that is required for high coupling efficiency, is comparatively complicated and expensive and is not described in detail in that article.
U.S. Pat. No. 5,535,296 describes an electrooptical coupling component with a bottom substrate, on which a first substrate with a plurality of optical waveguides disposed in the same plane and a second substrate with electrooptical converters, are disposed. The two substrates are aligned with one another with the aid of two alignment pins, which are introduced into precision-made openings of the first substrate. The row in the second substrate is dimensioned to fit the clearance between the two pins exactly. The beam path extends in a straight line between the ends of the optical waveguides and the associated optically active surfaces of the converters.
An electrooptical coupling component of the type defined at the outset is found in European Patent Application EP 0 699 931 A1. A first substrate includes optical waveguides having end surfaces that are beveled. An electrooptical converter is mounted on a second substrate in such a way that the optically sensitive surfaces of the converter face away from the second substrate. Beams emitted by the converter are coupled-in by total reflection from the end surface of the respectively associated optical waveguide. Metallizings corresponding to one another are provided both on the first and the second substrates and on the converter and the second substrate for jointly aligning the converter in the first substrate. The metallizings are disposed in such a way that if corresponding metallizings are superimposed congruently, the optical waveguides and converters are aligned with one another. The surface tension of solder that moistens the metallizings is utilized and the solder liquefies upon assembly and then solidifies. The incident thermal strains can cause a misadjustment after the two substrates have been assembled.